Sash balance



F. KILBERG SASH BALANCE Oct. 24, 1933.

Filed March 9, 1931 llllllllllll l 1 I ll 1 l MW I U I'WMWWHM W 1 ATTORNEVYS Patented Oct. 24, 1933 STA SASH BALANCE Frank Kilberg, Detroit, Mich.

Application March 9, 1931. Serial No; 521,130

2 Claims.

The present invention pertains to a novel sash balance spring intended especially for use in connection with sliding sash windows.

v According to the present practice, a separate spring unit is required for each of the sashes,

and it is customary to cut a cavity in the window frame at each side of the parting strip to receive the spring units. The over-all width of two adjacent cavities formed in this manner extends a over the major portion of the width of the frame member and hence weakens it considerably at this point. The spring units are held by screws, and considerable difficulty in supporting the units is encountered if the screw holes become worn or the-wood rots. V

The principal object of the invention is to overcome these difficulties, first by reducing the over-all width of the cavities and second by providing a supporting means other than screws. According to the invention, a single cavity is cut for both spring units and is so positioned as to be bisected lengthwise by the overhead parting strip. The pulleys are mounted in a receptacle which is fitted into the cavity, and the base of the receptacle has a longitudinal indentation which receives the upper parting strip, whereby the strip alone serves asthe support for the receptacle and pulleys. Moreover, the pulleys are so mounted in the receptacle as to overlap the indentation in the receptaclaso that at least a portion of the space behind the parting strip is utilized to house the pulleys.

The invention is fully disclosed by way of example in the following description and in the accompanying drawing in which- Figure 1 is an elevation, partly in section, of the device of the invention assembled in a window frame;

Fig. 2 is a vertical section at right angles to Fi 1;

Fig. 3 is a sectional View of to receive a cable; I

Fig. 4 is a section, partly in elevation, corresponding to Fig. 3 and at right angles thereto;

Fig. 5 is a perspective View of the double receptacle;

Fig.6 is an elevation of the pulley casing, at the inner side thereof, and

Fig. 7 is an elevation of the pulley at the inner side thereof.

Reference to these views will now be made by use of like characters which are employed to designate corresponding parts throughout.

In Figures land 2 is illustrated a rectangular window frame 1 of the conventional type having the device modified a pair of vertically slidable sashes 2 mounted therein. The sashes'are to be counter-balanced by springs concealed in the window frame, and the invention pertains to a novel structure and assembly for this purpose as already stated. Two such balance springs are necessary, one for each sash, and the invention provides a unitarydouble receptacle for maintaining the springs.

The receptacle is shown more clearly in Fig. 5 and consists of a base 3 with opposite parallel side walls 4. The base is indented longitudinally as at 5 midway between the side walls and parallel thereto to form a groove 6 for receivingone of the parting strips in the window frame structure as will presently appear.

The receptacle is preferably mounted in the header 7 of the window frame and accordingly is formed with a single cavity 8 into which the. receptacle is fitted. The receptacle is located so that the groove 6 is in line with the upper parting strip 9, whereupon this strip is received in the groove when installed. In this position, the parting strip constitutes the support for the receptacle, and the strip is in turn further sup ported by one of the vertical parting strips 10 upon which an end of the strip 9 rests as shown more clearly in Figure 1. I

The indentation 5 co-operates with the side walls 4 in forming a pair of channels 11 in the base of the receptacle as clearly shown in Figs. 2, 4 and 5. Into each of these channels is fitted a pulley casing comprising a back wall 12 abutting the corresponding side wall 4 and having a marginal flange 13 of the width of one of the channels 11. A right angular lug 14 is formed integral with the back 12 adjacent each of the lower ends of the flange 13 and is spaced therefrom to form a guideway 15' for a band as will presently appear. The

lower side of each lug rests upon the base 3 to provide additional bearing for the casing. The top of the flange 13 is curvedat 16 to receive a pulley, and the back 12 is formed with an inwardly extending bearing member 1'7 at the center of the curve 16.

The pulley received in the casing comprises a back member 18 with an inwardly extending cylindrical wall 19. A bearing member 20' extends inwardly from the center of the wall 18 and is received in the member 1'7 as shown in Fig. 2. In this position, the wall 19 is concentric with and slightly spaced from the curved wall 16. A flange 21 is formed on the wall 19 and abuts the curved part of the wall 13 to close the space between the walls. It will also be seen in Fig. 2 that the wall 19 in the assembled device extends over and overlaps the indentation 5.

The parts 19 and 21 have two inwardly converging notches 22 close to each other to form a lug 23 for anchoring one end of a coil spring 24, the other end of which is secured in a notch 25 cut in the bearing member 17. The lug 23 serves as the anchor for a band 26 wound on the pulley and carried downwardly through one of the guideways 15 into the window frame, along the inner edge of one of the vertical frame members, where it is secured as at 2'? to one of the sashes 2. The base 3 of the receptacle is relieved at 3 at one end of each channel llto accommodate the band passing therethrough. It will be evident that an assembly such as described is provided adjacent each of the side walls 4 of the receptacle, so that there is a band 26 for each sash. A tie bolt 28 is passed through the walls 4 and inner bearings 20 to provide a journal for the pulleys. Between the confronting walls 18 of the pulleys is inserted a spacing washer 29 on the bolt 28.

The springs 24 are placed under proper tension as in conventional sash balance springs. While the prior constructions require two separate cavities in the window frame at opposite sides of the parting strip for a pair of balance springs, the present invention requires only a single cavity. Moreover, a portion of the space behind the parting strip is utilized inasmuch as the pulleys extend partly over the parting strip as shown in Fig. 2. Thus, the overall width of the cavities in the window frame is considerably reduced. This feature is importan since the cavities cut in the usual manner extend over a considerable portion of the thickness of one of the window frame members and hence weaken it. A saving of even half-inch in the over-all width of the cavities is valuable. Moreover, the device of this invention requires no supporting screws inasmuch as it is supported by one of the parting strips, whereas the prior assemblies require attaching screws and involve considerable difficulty when the screw holes become enlarged or when the wood rots at the screw holes.

Figs. 3 and 4 show a modified construction wherein a cable is used instead of a steel band. Before assembling the pulley in its casing, a flanged ring 30 is fitted on the cylindrical wall pulley at that end which lies nearer the back 12 of the casing. The cylindrical wall of the ring 30 is preferably keyed into the pulley at several points 31 to prevent slipping. Instead of a steel band, a cable 32 is passed through a pair of apertures 33 in the ring and has one end knotted at 34 inside of the ring so that it will not be pulled out of the ring. The cable is wound around the pulley and passed through one of the guides 15 in the same manner as the steel band. Although only one such guide is necessary in each casing,

two guides are formed in order that the casings may be used interchangeably in either of the grooves 11.

As indicated in Fig. 2, the base 3 is exposed to the sash space for both the inner and outer sash, the opening of the window frame header extending to such space, so that, in service, the base 3 practically forms a portion of the upper wall of the sash space. To prevent any possible tilting,

the side walls 4 abut the side walls of the opening, the result being that the structure is supported by the upper parting strip of the window frame and requires no other fastening means. From this it can be understood that by simply removing the upper parting strip 9, the structure can be inserted or removed bodily from the frame, thus enabling the structure to be readily applied to frames already in position it being necessary only to remove the parting strip and cut the opening to receive the structure, the parting strip being restored after the fixture has been inserted.

And since the sole support is such parting strip and the latter extends above the bottom plane of the base but a small distance, it can be understood that the space between the side walls is free for the reception of the tensioned rolls, so that the axial length of each roll can approach a length equal to half the space, it being essential only that the rolls be kept spaced apart a distance suflicient only to prevent interference between them in the operation of the individual windows. As indicated, a small washer 29 serves to retain the rolls against such interference, so that it is possible that the spacing between the rollsis less than the width of the parting strip. Consequently, although the overall space is limited, it is possible to utilize springs of sufficient width and power to ensure the balancing of the sash, and at the same time obtain the necessary strength of connections between the sash and the roll to provide for durable installations, whether the connections be in the form of the band 26 or the cords 32.

Although specific embodiments of the invention have been illustrated and described, it will be apparent that various alterations in the details of construction may be made without departing from the scope of the invention as indicated by the appended claims.

What I claim is:

1. In sash balances, the combination with a window frame and its sash, of a spring-tensioned sash balance structure for the sash, the top of said frame-having an opening symmetrical to the upper parting strip and leading to the sash space of the frame, said sash balance structure including a substantially U-shaped frame having its base portion of a cross-sectional configuration to 1 partially enclose the parting strip and complete the sash-space wall at said opening, said structure frame having its vertical side walls abutting thev sidewalls of the window frame opening and forming a support for axially-alined .tensioned balance structures individual to the respective sash, whereby the sash balance structure will be supported solely by the parting strip and be, held against lateral tipping by the side walls of the frame to maintain stability of the sash balance structure while providing maximum space for the individual tensioning structures.

2. A combination as in claim 1 characterized by the individual tensioning structures each including a spring-enclosing casing having a periphery to receive the sash-supporting connection, said casings being carried by a journal supported by and forming a tie-bolt for the side walls of the U-shaped frame, said casings being spaced apart a distance less than the width of the parting strip. 

